Charge density identification in ion channels.

Biological channels permeate ions through cell membranes. Ion channels carry a permanent charge that has a significant role in determining channel's permeation properties such as selectivity to certain ions, current amplitude, etc. In this paper we deal with the determination of the permanent charge from current-voltage curves. The ion channel current behavior is modelled by Poisson-Nernst-Planck (PNP) equations system. Previous works on the fixed charge density identification problem contain several ill-posed steps and linearization of the nonlinear PNP system. We suggest here several methods to make these algorithms more stable and accurate.